Cutaneous epithelioid angiomatous nodule of the chest wall with expression of estrogen receptor: a mimic of carcinoma and a potential diagnostic pitfall.

Cutaneous epithelioid angiomatous nodule (CEAN) is a rare vascular proliferation that develops on the trunk and extremities. The lesion arises over weeks to months and affects both sexes without age predilection. Histologically, CEAN is characterized by a circumscribed proliferation of epithelioid endothelial cells in the superficial dermis with a background of lymphocytes, plasma cells and eosinophils. The epithelioid cells are positive for CD31, CD34 and/or D2-40. We report a case of CEAN that had remained stable for more than 30 years on the chest wall of a woman with a history of breast cancer. The lesional cells were epithelioid in appearance and positive for estrogen receptor (ER), raising suspicion for breast carcinoma. However, the cells were positive for CD31, CD34, D2-40 and EMA (epithelial membrane antigen); they were negative for cytokeratins, carcinoembryonic antigen (CEA), CD1a, gross cystic disease fluid protein (GCDFP-15), S-100, a melanocytic cocktail, HHV-8 and progesterone receptor. The histologic and immunohistochemical features, including a low proliferation index (10% by Ki-67), helped to distinguish this lesion from carcinoma and other vascular lesions. This is the most comprehensive immunohistochemical profile reported for CEAN to date and the first time that ER expression has been described.